Abstract: A battery powered radio programmable remote switch controller and a separate hand held programming unit (programmer) designed to conserve the life of the life of the controller batteries using a combination of low voltage circuitry in the controller and a magnetic switch in the controller that is triggered by the programmer. When brought into proximity with the controller, a magnet in the programmer activates a magnetic switch in the controller which energizes a radio receiver in the controller to receive programming transmitted by the programmer. After downloading the program, removal of the programmer from the proximity of the controller deactivates the magnetic switch turning off the radio receiver, thereby saving over 99% of the power otherwise required to continuously monitor for a radio signal.

Abstract: The device comprises two power supply terminals, a local control terminal and remote control and presence detection terminals. It can operate in fully autonomous manner, the power supply terminals being connected to a voltage supply source by means of a local control switch, closing of which causes excitation of a coil of the electro-magnet. It can also operate in conjunction with a communication module. In this case, the terminals are permanently supplied by the source, the local control terminal is connected to one of the power supply terminals by a local control switch and the remote control and presence detection terminals are connected to the module. The device automatically detects the presence of the module and causes excitation of the coil if the supply voltage is sufficient and if a control signal is applied to it either by the local control switch or by the module.

Abstract: A method and a device for regulated actuation of a proportionally operated solenoid valve are described. The described method and the described device are distinguished by the fact that the actuation of the solenoid valve takes place under consideration for the regulating processes which were necessary prior to such time in order to operate the solenoid valve according to specifications.

Abstract: An occupancy sensor is provided that can operate within an extended range of AC and DC input voltages, enabling the sensor to be used in different electrical environments. The sensor draws substantially only an amount of current required by the sensor at the moment, which reduces power waste. The sensor includes a relay that de-energizes when occupancy is sensed and energizes when occupancy is not sensed. This reduces peak sensor current, permitting the sensor to maintain a more constant average current. A shutdown mode is provided to prevent sensor damage or destruction should excessive output current be drawn from the sensor. The sensor also includes a second output at which occupancy signals are provided when an occupancy signal is present at the first output.

Abstract: A device for controlling an electromechanical actuator with an actuating element and an actuating drive. The actuating drive includes an electromagnet which has a core and a coil. The actuating drive, furthermore, has a moveable armature plate. A controller is provided, the control variable of which is the current through the coil and the actuating variable of which is a voltage applied to the coil. A voltage source generates a supply voltage and a pulse width modulator modulates the actuating variable as a function of the supply voltage.

Abstract: A compact gas-expansion-type power source breaker by which a power supply circuit can be forcedly and surely isolated only in case of abnormalities such as short-circuiting of a wire harness or collision of road vehicles is provided. A lock 18 for constraining movement of a shaft 16 is set in a locked state by means of pushing force for constraining the movement of the shaft 16 forcedly provided by a reset spring 19 on one hand, and is connected via a lock operation plate 20 with a piston 21 for forcedly providing a reverse pushing force beyond the pushing force of the reset spring 19 sublimation of a gaseous actuating reagent 23 contained in a igniter 22 on the other hand.

Abstract: A transformer structured emergency stop switch (10) incorporates a first core member (14) wound with primary and secondary windings, and a second core member (15) which at normal times contacts with the first core member (14) under spring force and in an emergency is separated therefrom by a push button (16). Several transformer structured emergency stop switches (10) are connected in series to make up an emergency stop switch circuit.

Abstract: A method of programming one or more relay based electrical devices comprises the steps of selecting an electrical device to program, switching the relay from a first state to a second state, and applying a time varying signal to the relay associated with the selected device. The method also includes the steps of counting signal transitions occurring during the switching of the relay, and comparing the counted signal transitions to a predetermined value. The method further includes the step of programming the device based on the comparison step. Accordingly, the programming methodology advantageously enables programming of the device by employing the switching time period of the relay which allows for elimination of a separate dedicated programming terminal.

Abstract: A combined ground fault and arc fault circuit interrupter includes a differential current transformer, a hot electrical line and a neutral electrical line passing through the current transformer and forming the primary thereof, an asymmetrical current transformer having a core through which the hot and common electrical leads pass, and a secondary wound on the core for producing a signal more strongly responsive to the current in the common line than in the hot line. An arc fault detector is connected to the secondary of the second transformer, while a ground fault detector is connected to the secondary of the first transformer, and the outputs of the ground fault and arc fault detectors are both connected to a circuit interrupter arranged for disconnecting the circuit when either a ground fault or an arc fault is detected.

Abstract: An assembly that engages a component to a computer system includes a cover adapted to retain the component and to be inserted within a chassis of the computer system. A slide movably coupled to the cover has a proximal position associated with inserting the cover into the chassis and a distal position associated with withdrawing the cover from the chassis. A detector coupled to a lock and to the slide detects movement of the slide to actuate the lock. The lock is coupled to the slide and to the detector, and blocks movement of the slide towards the distal point when the lock is in an engaged state.

Abstract: An electromagnetic operator includes first and second coils wound coaxially An armature partially surrounds the coils for channeling flux during energization of the coils. The armature may be formed of a bent plate and secured to a ferromagnetic support. A control circuit applies energizing signals to the coils during operation. Both coils are energized during an initial phase of operation. One of the coils is subsequently released or de-energized automatically. A timing circuit removes current from the second coil after a variable time period. The time period may be a function of the configuration of the timing circuit, such as an RC time constant, and of the energizing signal.

Abstract: An apparatus that can be used to jump-start a car that has a weak battery. It includes a battery booster pack or a battery booster cable that is polarity sensitive and can detect proper and improper connections before providing path for electric current. This apparatus eliminates the danger of reverse connections, shorts, fires, spark firing and battery explosion. The apparatus requires no separate switching mechanism to turn power on or power off. It also does not require the imperfect human judgment of any indication device to determine correct or incorrect connection. The clamps detect for the correct polarity and automatically control the power. Power turns on once a good connection has been made. If user makes a wrong connection, there will be no power but its warning signal will go off. Once a clamp is dislodged from the battery terminal, it automatically turns power off without the need to deactivate a switch.

Abstract: An anti-reactivation safety device for an electrical load-bearing device, including a power input line for delivering current from a power source across the anti-reactivation device to the load-bearing device. A current transfer switch positioned along the power-input line is provided. The current transfer switch includes a switch for engagement in an open position and in a closed position to thereby control the flow of current across the power-input line. The anti-reactivation safety device further includes a power return line. A latch circuit, linked with the power return line and with the current transfer switch, is provided for biasing the switch in an open position and in a closed position. The latch circuit includes a current divider. The anti-reactivation safety device includes a load sensor circuit for selectively engaging the latch circuit.

Abstract: A control apparatus for an electromagnetic actuator for driving a mechanical element by using an electromagnetic coil. The control apparatus includes a circulation circuit for circulating current to be supplied to the electromagnetic coil, a capacitor provided in the circulation circuit and to be charged by the current flowing through the circulation circuit, and a unit for, when the current supplied to the electromagnetic coil is stopped, forming a discharge path for discharging the capacitor and flowing current to an opposite direction through the electromagnetic coil. The current supplied to the electromagnetic coil is charged in the capacitor, then when the current having been supplied to the electromagnetic coil is stopped, the electric charge thus accumulated in the capacitor is discharged thereby to flow current to the opposite direction through the electromagnetic coil.

Abstract: Two or more electric lines which transmit switching signals are monitored for short circuits. A difference voltage other than zero is at least intermittently applied to the lines which carry switching signals. The actual difference voltage between two lines is essentially continuously determined and a fault recognition signal representative of a short circuit between the two lines is produced when the measured difference voltage plot or the measured difference voltage differs from a predetermined reference voltage plot or from a predetermined reference voltage. An apparatus including a signal generator and an evaluation circuit determines when the measured voltage plot or voltage differs from the reference voltage or reference voltage plot and generates a signal with which the electric lines can be interrupted.

Abstract: A method and apparatus for the recognition of an armature drop off in an electromagnetically actuated device supplies an on/off controlled switching current to the solenoid coil of the device. A high level of current is caused to flow through the coil for attracting the armature, and reduced level of current is applied to the coil for holding the solenoid armature in its on position. If the armature should be caused to drop off from its on position by a mechanical shock, a transitory expansion in the period of the switching current occurs, due to the sudden decrease in magnetic circuit inductance. This increased switching current period is detected and compared to a predetermined threshold value. If the detected period exceeds the threshold value, it is recognized as an armature drop off, and corrective action can be taken immediately. An alternate embodiment detects a sudden increase in the holding current amplitude as an indicator of armature drop off.

Abstract: An automatic transfer switch apparatus for use with a stand-alone generator, for supplying emergency power to a residence or small business. The automatic transfer switch apparatus is configured to sense a utility line failure, start up and stabilize the generator, and switch over the household circuits from the utility to the generator, and switch back when the utility recovers. A load-shedding feature is provided for shedding and restoring different circuits within the residence, that represent loads of different priority, with loads being shed and restored, according to their priority.

Abstract: A load driver circuit (10) includes an output driver (11) suitable for driving an inductive load (13). An output clamp circuit (15) clamps the output (12) to a high voltage during turn-off of the output driver (11). An open load detect circuit (26) clamps the output (12) to a lower voltage when the load (13) has an open circuit fault. A power fault voltage detect circuit (28) clamps the output (12) to another low voltage during a power fault condition.

Abstract: A radioisotope proximity sensor is provided for detecting proximity or distance to a nearby object containing a small radiation source complementary to the sensor. The output of the sensor is amplified or compared to determine the distance or proximity. The radioisotope proximity sensor is unaffected by magnetic fields over the short sensing distances. It is also unaffected by environmental contamination when the appropriate radiosource/detector combination is used. The radioisotope proximity sensor is easily shielded from electrostatic or electromagnetic noise, and the radiation source can be small, easily incorporated, and requires no external power or connections to affect mechanical reliability or impede armature movement.

Abstract: An apparatus for independent voltage, air pressure, and/or fluid pressure control of multiple material or coating applicators, such as paint spray guns, includes a multiple gun control board that allows a single power supply to provide voltage to a plurality of paint guns and an independent gun control board that can output a different voltage signal for each gun to generate different gun operating voltages, different air pressures, and/or different fluid pressures. The independent gun control board includes a separate relay and potentiometer for each gun to be controlled. The potentiometer is adjustable so that the output voltage of the independent gun control board can be varied. The output voltage can be used to control the paint spray gun operating voltage and/or be sent to a pressure transducer to adjust the air and/or fluid pressure at which the triggered gun operates.

Abstract: A relay control circuit enables releasing of welding of contacts in a short period by applying an bombardment pulse effective for welded contacts of the relay. Welded contacts of a relay are detected and subsequently input a signal to a microcomputer. A first driver is connected to an output port of the microcomputer which controls the relay, and a second driver is provided to another output port for driving the relay in parallel. This configuration allows to drive the first and second drivers alternately when contacts of the relay are welded, in order to apply an effective bombardment pulse for ensuring rapid separation of the welded contacts.

Abstract: An electronic locking system with an access-control solenoid for controlling the operation of a locking mechanism is substantially immune to "hot-wiring." The locking system includes an actuating circuit for energizing the access-control solenoid. The actuating circuit is responsive to a modulated drive signal of a selected frequency to apply current through the solenoid to retract its plunger, while blocking externally applied DC voltages from reaching the solenoid. When an access code is entered through an input device, a control circuit of the locking system verifies the access code. When the code is verified, the control circuit generates the modulated drive signal to energize the solenoid to retract the plunger, thereby allowing the locking mechanism to be unlocked. After the plunger is retracted, the frequency of the modulated drive signal is changed to reduce the power consumption for retaining the plunger in its retracted position.

Abstract: Emergency shut-down circuit is provided for a multiplexed circuit. The emergency shut-down circuit includes a plurality of contacts arrayed in parallel to each other and which are synchronously opened and closed. A plurality of electromagnetic contactors are operated according to a open or closed state of each of the plurality of emergency shut-down switches and are connected in series to a main circuit power circuit for a motor.

Abstract: An electromechanical switching device includes at least one moveable contact and an associated drive in a device housing. Magnetic field sensors which are disposed at a suitable location inside and/or outside the device housing detect magnetic field values that are each linked to one of a plurality of switching states. The device housing has a switching handle which is intended for manual release. Through the use of a miniature inductance element with a ferrite core as a highly sensitive magnetic field sensor, a position of the switching handle or of a part coupled thereto is monitored and/or a current flowing in the switching device is detected.

Abstract: A system and method for controlling relays. The method may comprise receiving one or more input commands for a plurality of relays, with the plurality of relays including a first relay, and a last relay, initiating actuation of the first relay after receiving the input relay commands, and initiating actuation of the last relay after initiating actuation of the first relay. Initiating actuation of the last relay does not wait for a debounce of the first relay. The method waits a debounce period after initiating actuation of the last relay. The debounce period operates to debounce the last relay and the first relay. One or more second relays may also be included in the debounce sequence. The relays may be latching or non-latching relays. The method may determine if another relay is required to be actuated after initiating actuation of each relay. One of the input commands may include a debounce mode input. A delayed debounce mode debounces the plurality of relays only after the last relay has been actuated.

Abstract: An apparatus and a method for driving a solenoid valve, which includes a coil and a movable armature. To move the armature, current and/or voltage is applied to the coil in a clocked manner. By varying the driving, the solenoid valve can be operated optionally as a control valve or as a relief valve.

Abstract: An apparatus and method for controlling a solenoid valve wherein the flow rate of the valve relative to a specific percent duty cycle may be varied. The controller is such that after the desired flow of the solenoid valve is determined, the frequency and percent duty cycle of an output signal controlling the solenoid valve is varied. Such a controller utilizes varying frequencies to provide multiple slope flow rates with a single passage solenoid valve.

Abstract: A computer monitor system including an infrared motion detecting switch that deactivates the monitor after a predetermined delay during which no movement is detected in the vicinity of the monitor. The system is designed to prevent damage to the screens through excessive use.

Abstract: A fire door opener and method of electronically controlling the door descent speed is described. The operator includes a DC brake solenoid coupled to an AC motor drive system with an inline gear reducer and an electronically controlled descent device with battery backup power. If the brake is disengaged, the door will drop by overcoming the internal inertia and friction in the inline gear reducer. Speed of descent is controlled electronically by measuring the descent speed of the fire door at its limit shaft and electrically modulating the brake engagement using the DC solenoid.

Abstract: An apparatus for the thermal binding of sheets includes at least one support (5-5a-5B) for a binding element (3). The binding element has a binding back on which an amount of glue (4), which melts under the influence of heat, is provided. A heating element (6) co-operating with the support (5-5A-5B) or forming part thereof, a detection device (7) to detect the presence of the binding element (3) in the apparatus (1) and a control/switching device (8), which is connected to the detection device (7) and is connected to the heating element (6) in order to switch it on and/or off, are also included. The detection device (7) is applied underneath the support (5-5A-5B).

Abstract: A monitoring circuit which allows for the complete monitoring, at short intervals, of several signal inputs and consequently of signal outputs without having to take into account external interference, like for instance the execution time in the case of light barriers, is obtained in that the signal inputs are connected through two capacitors to at least one relay, in that the signal inputs apply a potential to the capacitors while oscillating and in that the capacitors discharge into the relays while oscillating.

Abstract: A microprocessor-controlled electronic thermostat system and method that detects the status of a thermostat output relay to determine if the relay has been set to a state as requested by the microprocessor and, if not, providing a boosted or increased voltage to the output relay in an attempt to correct the relay setting. Preferably, the system determines if the output relay is correctly turned off as requested by the microprocessor, and, if it is not, a first boosted voltage value is provided to the output relay in an attempt to turn the relay off. If this fails, a second higher boosted voltage value is provided to turn the output relay off. This continues periodically until an off condition is detected.

Abstract: A control device for an electromechanical circuit breaker device. The device includes a bistable type electromagnet to deliberately control power contacts and a monostable trip electromagnet to open the contacts in case of a fault. The bistable electromagnetic coil and the trip electromagnetic coil are placed in parallel with a capacitance. The control device includes a maintained control switch and an H bridge of two-way switches associated with the bistable coil. The control device acts on the bridge of switches and a trip switch opens the contacts depending on the current in the coils measured by sensors.

Abstract: A battery powered irrigation valve controller designed to conserve the life of both the low voltage battery source which operates the microprocessor circuitry as well as the high voltage battery source which operates the external valve solenoids. Energy leakage from the high voltage battery source is prevented by maintaining the primary capacitor in a discharged state and delaying the charging of this capacitor until just before it is to be discharged to the valve solenoid. Unnecessary depletion of the high voltage battery source is also accomplished by isolating this source from the primary capacitor immediately prior to discharge, thereby avoiding a draw of energy from the high voltage battery source itself during discharge. The low voltage battery source which powers the computer circuitry is conserved through the action of the microprocessor which does not run in a continuous current consuming mode, but which remains dormant except for periodic sampling.

Abstract: A reset lockout for a control device which functions to control and monitor the essentially simultaneous energization of two electromagnets (61, 62) in response to a respective electric signal (S1, S2) applied to said electromagnets essentially simultaneously, wherein each electromagnet includes an element (71, 72) which in a non-energized state of the electromagnet takes a first inactive, normal position and which upon activation of the electromagnet is displaceable to a second active terminal position, wherein the control device is constructed to ensure that the displaceable elements (71, 72) of both electromagnets (61, 62) will be moved to their respective active end positions essentially simultaneously and then remain in said end positions provided that both signals (S1, S2) are applied essentially simultaneously and then both maintained.

Abstract: An under voltage trip device for low and medium voltage breakers is disclosed. A first power supply receives unregulated power from a control voltage supply which is rectified and regulated with portions of the power supply monitored by a processor. The output of the first power supply is supplied to a second power supply which allows pulsing modulating power to be supplied to a solenoid connected thereto. The current supplied to the solenoid is measured and calculated by the processor and stored therein as well as being compared to stored values, thereby determining solenoid armature position and predicting or warning of solenoid failure. Connected to the second power supply is a third power supply which operates in a voltage regulator supply mode and a switcher mode during start-up and continuous running operation respectively, such mode being controlled by the processor.

Abstract: In a circuit configuration and a method for triggering at least one electrically triggerable magnet with a suitably targeted triggering power, the magnet switches a switching element into a desired switching position in which the switching element is retained. After the switchover of the switching element by the magnet into the desired switching position, the magnet is at least briefly repeatedly acted upon at predetermined time intervals with a triggering power corresponding to a desired switching position.

Abstract: A very low cost method of driving the coil of a meter disconnect switch utilizes the 60 Hz signals from an existing power supply rectifier to generate properly phased gate drive signals to SCRS, with only one stage of isolation.

Abstract: A priority control system is disclosed for controlling multiple secondary load devices, and one priority load device. The secondary load devices can be randomly controlled at any time, except when the priority load device is activated, in which case, all secondary load devices are deactivated. The priority control system has a first relay which relays power to a plurality of secondary relays corresponding to the secondary load devices. The first relay is biased such that it normally provides power to the secondary relays. The first relay also has a priority position which is the non-biased position, for providing power to the priority load device. The first relay is activated by a priority control device which switches system power from the secondary relays to the priority load device. A priority timer circuit is provided to limit the time the first relay is in the priority position, regardless of a possible malfunction in the priority control device.

Abstract: A device for controlling a switching relay to deliver power to a load. The switching relay selectively couples a hot leg of a utility power supply to the load. The load is coupled to a neutral wire of the utility power supply. The device includes a sensor for detecting whether an area is occupied. If the sensor indicates that the area is occupied and the load is powered off, the device monitors the line voltage for a zero crossing. Upon detecting a zero crossing, an amount of time to a subsequent zero crossing is measured and stored. Then, the device waits the amount of time between zero crossings, less a delay time for closing the contacts of the relay, and initiates a closing of the contacts of the relay. Similarly, when the sensor detects that the area has not been occupied for a predetermined amount of time and the load is powered on, the line voltage is monitored for a zero crossing and a time to a subsequent zero crossing is measured and stored.

Abstract: A microprocessor-based control for a solenoid operated device, wherein the microprocessor employs a tri-state output to achieve fast, precise control of the device without overburdening the microprocessor. The system has three selectable control modes: a first control mode in which the solenoid is de-energized, a second control mode in which the solenoid is fully energized, and a third control mode in which the solenoid is pulse-width-modulated. The various control modes are selected by the microprocessor and indicated by the logic level of a tri-state output. In the first and second control modes, indicated by first and second logic levels, the energization state of the solenoid is controlled directly by the microprocessor. In the third control mode, indicated by a third logic level, the energization state of the solenoid is controlled by an external PWM circuit based on PWM commands supplied to the PWM circuit by the microprocessor.

Abstract: The add-on smart socket adaptor integrates electric facilicities and/or home appliances to be an intelligent system for the home automation. The add-on smart socket adaptor has the add-on multiple different sensors to detect the complex environmental changes as the inputs of the programmed logic to make the complex decision function to generate the output to turn on and/or turn off the multiple different home appliances and electrical facilities smoothly, separately and cooperatively. The add-on smart socket also can be built-in to integrate with the home appliances and electrical facilities to have the home automation. The add-on smart socket adaptor provides the open platform and standard for the synthesis of home automation integrated system.

Abstract: A two wire detection device includes a relay switch setable to a high and a low impedance state and electrically coupled between a first terminal of an AC source and a first leg of a load, a second leg of which is connected to a second terminal of the AC source. The device includes an energy storage device electrically coupled to the first terminal of the AC source and electrically connected to the first leg of the load. Charge control means interposed between the first terminal of the AC source and the energy storage device regulate the voltage across the energy storage device. A detection control device is electrically connected across the energy storage device and to the switching device for detecting the presence of a condition for monitoring and setting the state of the switching device based thereon such that power is available to the detection control device regardless of the state of the switch.

Abstract: A safety system comprises separate safety circuits connected to a process to be safeguarded, each of which safety circuits are coupled to a data acquisition circuit via a retroaction-free element, which takes care of it that in the event of a malfunction occurring on the input of the data acquisition circuit, this malfunction will not affect the reliability and operational safety of each of the separate safety circuits.

Abstract: A power supply circuit is provided for use in combination with a load and an alternating current (AC) power source for selectively connecting and disconnecting the load and the AC power source. The load is connected between a neutral conductor of the AC power source and the power supply circuit. The power supply circuit is connected to a power or hot line conductor and a ground conductor of the AC power source. The power supply circuit comprises relay connected in series between the load and the line conductor; a control circuit for selectively operating the relay; and a transformer. The primary winding of the transformer is connected in series with the line conductor and the ground conductor for supplying power to the control circuit even when the load is disconnected from the AC power source. The power supply circuit comprises a switch in series with the primary winding of the potential transformer for interrupting the primary winding current at frequencies above the AC line frequency.

Abstract: A fail-safe fluid transfer control apparatus has full redundancy in the response to various inputs such as overfill probe signals, ground detection signals, and the like. Independent microprocessor controllers independently evaluate the inputs and each output control signals to close a respective relay when the inputs indicate that fluid transfer may commence. The relays are arranged in series such that both must be closed for a fluid transfer to commence. The control signals from each controller include a static signal and an alternating signal, both of which must be properly output to close its respective relay. Each controller monitors the state of each relay, and discontinues its control signals if either relay appears to be malfunctioning. Each controller runs an different, independently written firmware program to process the detected inputs to prevent a common firmware error.

Abstract: A control cabinet for distributing power to a plurality of automated independent and parallel operated loads. A plurality of control cabinets can be interfaced with control cable to be supervised by one main controller. The main controller distributes low voltage ac signals to each control cabinet, which transfers the low voltage signal into high voltage power distribution by a series of low and high voltage relays, thus eliminating the need for excess circuit boards and transformers normally associated with this task.

Abstract: A safety device includes a comparator circuit includes three resistors arranged in series. An IC has a positive pole coupled to the resistors and has a negative coupled to the positive pole of another IC which has a negative pole coupled to the resistors. A signal output circuit includes a transistor having a base connected to the ICs and having a collector coupled to a relay. The relay includes two common contacts for selectively contacting with two normally closed contacts and two normally open contacts so as to supply electric power to the common contacts when an electric appliance is coupled between the common contacts.

Abstract: Upon initiation of operation of a contactor from an unactuated condition to an actuated condition, the maximum magnitude of an initial current conducted to the coil of the contactor is determined. Once the contactor has been operated to the closed condition, the holding current is checked to determine if it exceeds a reference current. The reference current is a predetermined function of the maximum initial current. If the reference current is less than the holding current, a malfunction signal is provided. In another embodiment of the invention, a sensor is provided to sense the position of movable contacts connected with an armature of the contactor.

Abstract: The present invention disclosed and claimed herein comprises a backup power system to supply current to an electromechanical actuator (50) to position a mechanical device (52) to a fail-safe position upon failure of a primary electric power source (12). A capacitor (40) is provided for storing energy. The capacitor (40) is charged by the primary electric power source (12). A relay device (35) is also provided for disconnecting the primary control signal upon failure of the primary electric power source (12) and connecting the capacitor (40) to the electromechanical actuator (50) to supply electric current to the electromechanical actuator (50) to position the mechanical device (52) to a fail-safe position. The relay device (35) comprises a transistor (32) which is kept turned off by the primary electric power source (12) and upon failure of the primary electric power source (12), turns on and energizes an electric relay coil (34).